An Afghan army soldier has killed three US troops and wounded another in eastern Afghanistan, the US Defense Department has confirmed.

The Pentagon announced the development on Saturday, without providing details.

A spokesman for the provincial governor in Nangarhar province had said earlier on Saturday that the Afghan soldier was killed after the attack, which was carried out in Achin district.

Attahullah Khogyani would not elaborate on further details about the insider attack and what could have caused the incident. He said the Afghan commando was killed in the return fire and the incident came during a joint operation against potential attacks by Daesh, a Takfiri terrorist group based in Iraq and Syria that has gained a foothold in Nangarhar.

Afghanistan has seen attacks by military personnel on foreign forces some 15 years after the United States led a Western military campaign to oust the Taliban from power. In March, three US soldiers were killed in one such attack in Helmand, the volatile province where the Taliban still holds a grip.

The attack in Nangarhar comes as anti-US sentiments still run deep among Afghan police and military forces as many blame Washington for the continued bloodshed in the country. They say the US presence in Afghanistan continues to claim lives from civilians and security forces while attacks by the Taliban and other militant groups, such as Daesh, are also on the rise.

At least three Afghan police officers were killed on Saturday, when US warplanes opened fire on their gathering during an operation in Helmand. The US military command said in a statement that the Afghan policemen were killed in a so-called friendly fire. Both Afghan and US officials said they had launched investigations into the incident, which happened during a joint operation, this time against the Taliban.